Smooth hydrangea (Hydrangea arborescens), also sometimes called hills of snow or snowball hydrangea, is an especially easy-growing type that's native to areas of North America. It has clusters of pure white flowers from midsummer into autumn; the older flowers often fade to green before they turn brown and dry.
Oakleaf hydrangeas (H. quercifolia) grow panicle flowers on rangy stems with attractive, peeling bark. They're native to the United States and super-easy to grow in warm climates, but not hardy enough for much of the Midwest. If you live in Zone 5, an oakleaf is a good low-care option.
Vaughn's Lillie Oakleaf Hydrangea Bold only begins to describe stunning Vaughn's Lillie Hydrangea quercifolia. This selection features exceptionally full flower heads. It also tends to bloom more profusely than the average oakleaf hydrangea and has a compact habit. It grows 4 feet tall and 5 feet wide. Zones 5-9